Disorder of the coordinated C=C bond in the [Cu2Cl3(CH2=CH-CH2NH3)2]CuCl2 π-complex

The results of X-ray diffraction analysis of the zwitterionic olefinic pi-complex [Cu2Cl3(AAH)(2)]CuCl2 (AAH(+) = allylammonium cation) are presented: space group B2/b, a = 26.513(5), b = 7.553(2), c = 7.401(1) Angstrom, gamma = 96.36(2)degrees, V= 1472.9(9) Angstrom(3), Z = 4; R = 0.030 for 880 independent reflections with F(hkl) > 4 sigma(F). It is shown that the local disorder of the coordinated olefinic bond (known for this class of compounds) is due to the heterodesmic character of the structure, namely, to the increased weight of the nondirected electrostatic interactions in the loosely packed coordination core of Cu(I). This does not result in weakening of the Cu-(C=C) bonding but, just the opposite, favors additional activation of the olefinic bond by the electron-enriched chlorine atoms of the Cu2Cl3- ion.